Watertight, low power L.E.D. flashlight

ABSTRACT

A watertight, low power flashlight is disclosed that uses a voltage tripler and regulator that enables the use of a single AA or lithium battery. The voltage tripler is a “step-up power component” that raises the battery voltage from 1.5 to approximately 5 volts required to sufficiently energize the L.E.D.s. The flashlight also includes a lightweight, compact housing with an optional dimmer switch and a side-mounted “soft” on/off switch.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to flashlights with at least one light emitting diode (L.E.D.) and, more particularly, L.E.D. flashlights that are watertight, lightweight, and have low voltage requirements.

[0003] 2. Description of the Related Art

[0004] It is well known that L.E.D.s are more energy efficient, have longer lives, and are more mechanically reliable than incandescent bulbs. Because of these benefits, they are commonly used in small, portable lights such as flashlights.

[0005] L.E.D. flashlights found in the prior art generally consist of one or more L.E.D.s located inside a housing containing a plurality of batteries. Because L.E.D.s require 5 volts of D.C. current for optimal illumination, at least three AA or AAA batteries connected in a series are used. As a result, most bright L.E.D. flashlights have relatively large housings. When a L.E.D. flashlight with a smaller housing is desired, for example with a L.E.D. key ring or fob, a single battery may be used but that the flashlight's illumination will be substantially reduced.

SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide a lightweight, compact L.E.D flashlight

[0007] It is another object of the present invention to provide one L.E.D. flashlight that includes a step-up power converter that enables it to operate with fewer batteries normally used in an L.E.D. flashlight and without substantially reduced illumination.

[0008] It is a further object to the present invention provide such an L.E.D. flashlight that includes a water-tight housing and switches.

[0009] These and other objects are met by the lightweight, compact L.E.D. flashlight that uses a L.E.D. light circuit, a power circuit and a voltage multiplying circuit. In the preferred embodiment, the power circuit includes a soft momentary switch and a soft dimmer switch connected to a single AA or AAA battery. The L.E.D. light circuit includes one to three L.E.D.s that optimally operate at 5.0 volts. The voltage multiplying circuit raises the battery voltage from 1.5 to approximately 5 volts. The flashlight also includes a watertight housing

DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is perspective view of the first embodiment of the L.E.D. flashlight disclosed herein.

[0011]FIG. 2 is a top plan view of the embodiment shown in FIG. 1.

[0012]FIG. 3 is a right side elevational view of the embodiment shown in FIG. 1.

[0013]FIG. 4 is a front elevational view of the embodiment shown in FIG. 1.

[0014]FIG. 5 is a rear elevational view of the embodiment shown in FIG. 1.

[0015]FIG. 6 is a perspective view of the second embodiment of the invention.

[0016]FIG. 7 is a top plan view of the embodiment shown in FIG. 6.

[0017]FIG. 8 is a sectional side elevational view of the embodiment shown in FIG. 1.

[0018]FIG. 9 is a sectional bottom plan view of the embodiment shown in FIG. 1.

[0019]FIG. 10 is a side elevational view of the side and top plates.

[0020]FIG. 11 is a right side elevational view of the side and top plates.

[0021]FIG. 12 is a sectional top plan view of the second embodiment of the invention.

[0022]FIG. 13 is a sectional, side elevational view of the second embodiment of the invention.

[0023]FIG. 14 is a left side elevational view of the side plate used in the second embodiment of the invention.

[0024]FIG. 15 is a right side elevational view of the side plate used in the second embodiment of the invention.

[0025]FIG. 16 is a schematic diagram of the electrical circuits used in the first embodiment of the L.E.D. flashlight.

[0026]FIG. 17 is a schematic diagram of the electrical circuits used in the second embodiment of the L.E.D. flashlight.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0027] Referring to the accompanying Figs., there is shown and described a lightweight, compact multiple and single L.E.D. flashlight, denoted 10, 10′, respectively. Each embodiment 10, 10′, shown more clearly in FIGS. 1-5, and 6, 7, respectively, includes an elongated hollow main body 12, 12′, with a closed end 13′ and a transparent lens 28, 28′ that attaches over an open end 14, 14′, respectively. Each main body 12, 12′, which is made of a clear or colored plastic or similar material, is made of two halves 17, 18 that snap-fit together along the central longitudinal axis 19 of the main body 12 as shown in FIG. 1. Formed on the closed end 13, 13′ of the main body 12, 12′ is an optional key ring 20, 20′, respectively. On the double L.E.D. flashlight 10, an optional belt clip 36 is also provided.

[0028] On the multiple L.E.D. flashlight 10, hollow transversely aligned posts 22, 23 are formed on the inside surface of the first half component 17 and the second half component 18 on opposite ends of the main body 12, respectively. During assembly, screws 38, 39 are extended through holes formed on opposite half components 17, 18 and connect to the posts 22, 23, respectively (see FIG. 8) to hold the two half components 17, 18 together. In the single L.E.D. flashlight 10′, the posts 22, 23 and screws 38, 39 are replaced with brackets (not shown) that enable the two half components 17, 18 to snap fit together. In both embodiments, a gasket 35, shown in FIG. 2, is located along the joining edges of the two half components 17, 18 that create a watertight seal.

[0029] As mentioned above, attached over the open end 14 of the main body 12 and 12′ is a transparent lens 28, 28′, respectively, each made of plastic or similar material. In both embodiments, the lens 28, 28′ snaps into the perimeter edges of two half components 17, 18 that form the open end 14.

[0030] As shown in FIGS. 8 and 12, formed on the outer surface of each main body 12, 12′ are two switch holes 30, 32 through which a main on/off switch button 34 and an optional dimmer switch button 40 extends, respectively.

[0031] In the first embodiment, an elongated printed circuit board 42 is longitudinally aligned inside the main body 12. As shown in FIGS. 10 and 11, aligned perpendicularly on the proximal end of the printed circuit board 42 is a smaller, multiple L.E.D. printed circuit board 43. In the second embodiment 10′, a smaller, elongated printed circuit board 45 is longitudinally aligned inside the main body 12′. As shown in FIGS. 14 and 15, longitudinally aligned on the proximal end of the circuit board 45 is an integrally formed neck 46 which contains terminals 94, 95 to which the terminals 68, 69 on the L.E.D. 65 connect. In both embodiments, the main printed circuit boards 42, 45 are slightly off-set from the longitudinal axis 19 of the main body 12, 12′ thereby creating a longitudinally aligned cavity 50, 50′ for a AA battery 55.

[0032] As shown in FIGS. 10 and 11, the multiple L.E.D. printed circuit board 43 has two L.E.D.s 65 connected thereto that face the open end 14 of the main body 12. Although there is shown two L.E.D.s 65 mounted on the L.E.D. printed circuit board 43, it should be understood that any desired number of the L.E.D.'s 65 can be used. Each of the L.E.D.s 65 includes a casing of a light, transparent material 66, such as a glass, having therein a light emitting diode 67. One terminal 68 of each L.E.D. 65 connects to a first terminal 92 located on the L.E.D. printed circuit board 43. The other terminal 69 of each L.E.D. 65 connects to a second terminal 93 located on the L.E.D. printed circuit board 43. The terminals 92, 93 are electrically connected to two terminals, 94, 95 located on the main printed circuit board 42 via wires 52, 53. As shown in FIGS. 12 and 13, and as mentioned above, the first and second terminals 68, 69 on the single L.E.D. 65 used in the second embodiment 10′ are directly connected to two terminals 94, 95 formed on the neck 46. In both embodiments, the L.E.D.'s 65 emit white light.

[0033] As also shown in FIGS. 10 and 14, attached to opposite ends of each printed circuit board 42, 45 respectively, are two contact strips 70, 72 that connect to the positive and negative terminals 56, 57, respectively, on a battery 55. In both embodiments, a single AA battery 55 is longitudinally aligned inside the battery cavity 50 and connected between the two contact strips 70, 72.

[0034]FIGS. 16 and 17 are schematics of the two printed circuit boards 42, 45 used in the first and second embodiments 10, 10′ of the flashlight, respectively. Each printed circuit board 42, 45 includes a light circuit 80, a power circuit 85, and a voltage multiplying circuit 90. The light circuit 80 includes at least one L.E.D. 65 connected to three NPN transistors 81-83 connected in a series to a CMOS semi-conductor 84. An optional dimmer switch 98 is connected between the CMOS semi-conductor 84 and the L.E.D. 65. The power circuit 85 includes a main on/off switch 95 and four NAND logic gales 86-89 that control the switch control logic and the brightness control logic. The voltage multiplying circuit 90 includes a synchronous boost converter 92 that connects to a 1.5 volt battery 55 that triples the voltage.

[0035] In the preferred embodiment, the synchronous boost converter 92 is a six lead thin SOT with a fixed frequency, step-up DC/DC converted capable of supplying 3.3V at 150 mA from a single AA cell input. Such converters contain an internal NMOS switch and a PMOS synchronous rectifier. An example of a synchronous boost converter (Model No. LTC 3400) that may be used is sold by Linear Technology Corporation located in Milpitas, Calif.

[0036] Table 1 lists the codes, names, and functions of the components shown in FIGS. 16, and 17.

[0037] In compliance with the statute, the invention described herein has been described in language more or less specific as to structural features. It should be understood, however, that the invention is not limited to the specific features shown, since the means and construction shown, is comprised only of the preferred embodiments for putting the invention into effect. The invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the amended claims, appropriately interpreted in accordance with the doctrine of equivalents. TABLE 1 Designator Qty Description C1 1 Miniature Electrolytic C2 1 Chip Capacitor C3 1 Chip Capacitor C4 1 Chi Capacitor C5 1 Miniature Electrolytic Capacitor C6 1 Chip Capacitor D1 1 Schottky Baffler Rectifier L1 1 Inductor LED1, LED2 2 Nichia White LED Lamp Q1 1 NPN Transistor Q2 1 NPN Transistor Q3 1 NPN Transistor R1 1 Chip Resistor R10 1 Chip Resistor R11 1 Chip Resistor R12 1 Chip Resistor R13 1 Chip Resistor R2 1 Chip Resistor R3 1 Chip Resistor R4 1 Chip Resistor R5 1 Chip Resistor R6 1 Chip Resistor R7 1 Chip Resistor R8 1 Chip Resistor R9 1 Chip Resistor S1 1 Rubber Key S2 1 Rubber Key U1 1 Synchronous Boost Converter U2 1 CMOS Quad 2-input NAND gate 

I claim:
 1. A flashlight comprising, a. housing having a center cavity; b. a transparent lens attached to said housing; c. printed circuit board disposed inside said housing, said printed circuit board including a power circuit and a voltage multiplier circuit that multiplies the voltage delivered by a battery connected to said power circuit; d. at least one L.E.D connected to said voltage multiplier circuit; e. an ON-OFF switch connected to said power circuit on said printed circuit board; and, f. a battery connected to said power circuit and used to energize said L.E.D.
 2. The flashlight as recited in claim 1, further including a dimmer switch connected to said power circuit.
 3. The flashlight as recited in claim 1, wherein said voltage multiplier circuit includes a synchronous boost converter.
 4. The flashlight as recited in claim 1, wherein said synchronous boost converter is capable of supplying 3.3 Volts at 150 MA.
 5. The flashlight as recited in claim 1, wherein said battery supplies 1.5 Volts.
 6. The flashlight as recited in claim 1, wherein said flashlight includes two L.E.D.s.
 7. The flashlight as recited in claim 1, further including a key ring attached to said housing.
 8. The flashlight as recited in claim 1, further including a belt clip attached to said housing.
 9. The flashlight as recited in claim 1, further including a reflector located inside said lens and disposed around said L.E.D.
 10. A flashlight comprising, a. housing having a center cavity; b. a transparent lens attached to said housing; c. printed circuit board disposed inside said housing, said printed circuit board including a power circuit and a voltage multiplier circuit that triples the voltage delivered by a battery connected to said power circuit; d. two L.E.D.s connected to said voltage multiplier circuit; e. an ON-OFF switch connected to said power circuit on said printed circuit board; and, f. a battery connected to said power circuit and used to energize said L.E.D, said battery provides 1.5 volts.
 11. The flashlight as recited in claim 10, further including a dimmer switch connected to said power circuit.
 12. The flashlight as recited in claim 11, wherein said housing is watertight.
 13. The flashlight as recited in claim 11, further including a key ring attached to said housing.
 14. The flashlight as recited in claim 11, further including a belt clip attached to said housing.
 15. The flashlight as recited in claim 11, further including a reflector located inside said lens and disposed around said L.E.D.'s.
 16. An L.E.D. flashlight, comprising: a. a housing; b. a battery; c. a power circuit that includes at least one battery and an on/off switch; d. a L.E.D. light circuit having at least one L.E.D. connected to said power circuit, and, e. a voltage multiplying circuit containing a synchronous boost converter connected between said power circuit and said L.E.D. light circuit. 